Antrim (ănˈtrĭm) [key], district (1991 pop. 48,000), 217 sq mi (562 sq km), NE Northern Ireland. The eastern and seaward area is a picturesque region of mountains and glens; to the west, where Antrim borders on Lough Neagh, lie the fertile valleys of the Bann and the Lagan rivers. Tourism is significant. The region is chiefly agricultural (oats, flax, potatoes). Fishing and cattle breeding are also important.